The objective is to determine quantitatively levels of innervation for human primary and permanent teeth and to compare such levels for primary teeth at various stages of resorption. At this point quantitations of innervation have been done for nine primary teeth at various stages of resorption. From data gathered so far, it appears that approximately 85% of axons entering primary teeth are unmyelinated. This figure is fairly constant in teeth examined so far. A linear correlation exists between number of myelinated axons and number of unmyelinated axons. This holds for both resorbed and unresorbed teeth. If this trend is supported in the remainder of the study, it would suggest that the number of unmyelinated axons can be approximated from the number of myelinated axons. A frequency distribution has been done for number of unmyelinated axons per Schwann cell. The most common arrangement is for four axons to be grouped within a single cell. However, numerous instances were found where ten or more axons were encompassed within a single Schwann cell. In resorbing teeth, several changes were noted. It appears that small numbers of axons degenerate fairly quickly at different places in the pulp. The resulting pattern at any one time is a pulp with relatively few altered axons, rather than many altered axons which are in a slower process of degeneration. Degeneration appears to follow a dystrophic pattern rather than a Wallerian pattern of degeneration. Calcified bodies have been frequently found adjacent to groups of axons, but their significance has not as yet been established.